Keywords

Abstract

Across the visual pathway strong monosynaptic connec
tions generate precise correlated activity between presy
naptic and postsynaptic neurons. The degree of this precise
correlated activity can be inferred from the monosynap
tic cross-correlogram peak-width. Retinogeniculate con
nections generate correlograms with very narrow peaks,
while geniculocortical or corticocortical peaks are wider.
While it is difﬁcult to determine the physiological parame
ters that contribute to the precision of the correlated ﬁring
in physiological experiments, a ﬁrst approach can be done
by computational modeling and simulation. In this article
we present a new integrate-and-ﬁre(IAF) neuron model de
signed and computationally optimized to analyse the con
tribution of the main physiological factors to the correlated
activity. Our results suggest that the precision of the corre
lated ﬁring generated by strong monosynaptic connections
is mostly determined by the EPSP time course of the con
nection and much less by other factors. The model stands
out to incorporate the modulation of the synaptic conduc
tance based on two alpha functions with different time
constants to independently analyse the inﬂuence of the rise
and decay times of the conductance on the correlated activ
ity. A Z-transformation of the synaptic conductance equa
tion turns it into a recursive function that signiﬁcantly in
creases the computational efﬁciency of the IAF model.